Helleborus plant named ‘COSEH 790’

ABSTRACT

A new and distinct cultivar of  Helleborus  plant named ‘COSEH 790’, characterized by its upright and uniformly mounded plant habit; uniform and freely flowering habit; dark green-colored leaves; long flowering period; single white-colored flowers tinged with light green; and good garden performance.

Botanical designation: Helleborus niger×Helleborus×sternii.

Cultivar denomination: ‘COSEH 790’.

BACKGROUND OF THE INVENTION

The present invention relates to a new and distinct cultivar ofHelleborus plant, botanically known as Helleborusniger×Helleborus×sternii, and hereinafter referred to by the name ‘COSEH790’.

The new Helleborus plant is a product of a planned breeding program inGlandorf, Germany. The objective of the breeding program was to createnew uniform Helleborus plants with unique and attractive plant habit,leaf and flower coloration and resistance to pests.

The new Helleborus plant originated from a cross-pollination conductedby the Inventor in Glandorf, Germany in November, 2003 of an unnamedproprietary seedling selection of Helleborus niger, not patented, as thefemale, or seed, parent with an unnamed proprietary seedling selectionof Helleborus×sternii, not patented, as the male, or pollen, parent. Thenew Helleborus plant was discovered and selected by the Inventor as asingle flowering plant from within the progeny of the statedcross-pollination grown in a controlled greenhouse environment inGlandorf, Germany in February, 2006.

Asexual reproduction of the new Helleborus plant by divisions in acontrolled greenhouse environment in Glandorf, Germany since March,2006, has shown that the unique features of this new Helleborus plantare stable and reproduced true to type in successive generations.

SUMMARY OF THE INVENTION

Plants of the new Helleborus have not been observed under all possibleenvironmental conditions and cultural practices. The phenotype may varysomewhat with variations in environmental conditions such as temperatureand light intensity without, however, any variance in genotype.

The following traits have been repeatedly observed and are determined tobe the unique characteristics of ‘COSEH 790’. These characteristics incombination distinguish ‘COSEH 790’ as a new and distinct Helleborusplant:

-   -   1. Upright and uniformly mounded plant habit.    -   2. Uniform and freely flowering habit.    -   3. Dark green-colored leaves.    -   4. Long flowering period.    -   5. Single white-colored flowers tinged with light green.    -   6. Good garden performance.

Compared to plants of the parent selections, plants of the newHelleborus are more uniformly mounded and are more uniformly and freelyflowering.

Plants of the new Helleborus can be compared to plants of Helleborusniger×Helleborus lividus ‘COSEH 710’, disclosed in U.S. Plant Pat. No.21,063. In side-by-side comparisons conducted in Glandorf, Germany,plants of the new Helleborus differed primarily from plants of ‘COSEH710’ in flower color as plants of ‘COSEH 710’ had light green-coloredflowers with reddish pink overtones. In addition, plants of the newHelleborus and ‘COSEH 710’ differed slightly in leaf color.

BRIEF DESCRIPTION OF THE PHOTOGRAPHS

The accompanying colored photographs illustrate the overall appearanceof the new Helleborus plant showing the colors as true as it isreasonably possible to obtain in colored reproductions of this type.Colors in the photographs may differ slightly from the color valuescited in the detailed botanical description which accurately describethe colors of the new Helleborus plant.

The photograph on the first sheet comprises a side perspective view of atypical flowering plant of ‘COSEH 790’ grown in a container.

The photograph on the second sheet is a close-up view of a typicalflowering plant of ‘COSEH 790’.

DETAILED BOTANICAL DESCRIPTION

The aforementioned photographs and following observations, measurementsand values describe plants grown in 15-cm containers during the winterin a glass-covered greenhouse in Glandorf, Germany and under conditionswhich closely approximate commercial Helleborus production. During theproduction of the plants, day temperatures ranged from 12° C. to 32° C.and night temperatures ranged from 3° C. to 18° C. Plants were 14 monthsold when the photographs and the description were taken. In thefollowing description, color references are made to The RoyalHorticultural Society Colour Chart, 2007 Edition, except where generalterms of ordinary dictionary significance are used.

-   Botanical classification: Helleborus niger×Helleborus×sternii ‘COSEH    790’.-   Parentage:    -   -   Female, or seed, parent.—Unnamed proprietary seedling            selection of Helleborus niger, not patented.        -   Male, or pollen, parent.—Unnamed proprietary seedling            selection of Helleborus×sternii, not patented.-   Propagation:    -   -   Type.—By tissue culture.        -   Time to initiate roots.—About two months at 12° C.        -   Time to produce a rooted young plant.—About six months at            4° C. to 15° C.        -   Root description.—Thick to thin, fleshy; white to brown in            color.        -   Rooting habit.—Sparse.-   Plant description:    -   -   Plant form and growth habit.—Herbaceous perennial; upright            and uniformly mounding plant habit with flowers held just            above the foliar plane; plant shape is globular; and            moderately vigorous growth habit.        -   Plant height.—About 37.9 cm.        -   Plant diameter (area of spread).—About 50.8 cm.-   Foliage description:    -   -   Arrangement.—Leaves arranged in a basal rosette; leaves            palmately compound with five leaflets per leaf.        -   Leaf length.—About 13.7 cm.        -   Leaf width.—About 14.5 cm.        -   Leaflet length.—About 8.9 cm.        -   Leaflet width.—About 4.3 cm.        -   Leaf shape.—Palmate; orbicular in outline.        -   Leaflet shape.—Broadly ovate to elliptic.        -   Leaflet apex.—Acute.        -   Leaflet base.—Attenuate.        -   Leaflet margin.—Sharply and coarsely serrate.        -   Leaflet texture, upper and lower surfaces.—Smooth, glabrous;            leathery.        -   Leaflet venation pattern.—Pinnate.        -   Leaflet color.—Developing leaves, upper surface: Close to            N137B. Developing leaves, lower surface: Close to 148A to            148B. Fully developed leaves, upper surface: Close to 147A;            venation, close to 144A. Fully developed leaves, lower            surface: Close to 147B; venation, close to 187A.        -   Petiole.—Length: About 11.7 cm. Diameter: About 6 mm.            Texture, upper and lower surfaces: Smooth, glabrous. Color,            upper and lower surfaces: Close to 146C; moderately to            heavily tinged and dotted with close to between 187A and            200B.-   Flower description:    -   -   Flower shape and habit.—Single rotate flowers arranged in            terminal and axillary cymes; freely and uniform flowering            habit with about 80 flowers and flower buds per plant;            flowers facing outwardly to slightly nodding and slightly            upright.        -   Fragrance.—None detected.        -   Natural flowering season.—Plants begin flowering about ten            months after planting; long flowering period; plants flower            from late winter to early spring in Germany.        -   Flower longevity on the plant.—About ten days; flowers not            persistent.        -   Flower buds.—Length: About 1.9 cm. Diameter: About 1.1 cm.            Shape: Ovate. Color: Close to 150D tinged with close to 177C            to 177D.        -   Inflorescence height.—About 31.3 cm.        -   Inflorescence diameter.—About 23.2 cm.        -   Flower diameter.—About 6.2 cm.        -   Flower depth (height).—About 2.8 cm.        -   Petals.—Transformed into nectaries.        -   Sepals.—Quantity and arrangement: Five arranged in a single            whorl. Length: About 3.2 cm. Width: About 2.5 cm. Shape:            Ovate to broadly obovate. Apex: Rounded. Margin: Entire.            Texture, upper and lower surfaces: Smooth, glabrous. Color:            When opening, upper surface: Close to 145D; towards the            base, close to 145B. When opening, lower surface: Close to            145C; towards the base, close to 146D. Fully opened, upper            surface: Close to 157D tinged with close to 145C to 145D and            150D; towards the base, close to 146D; with development,            color becoming closer to between 144B and 145A. Fully            opened, lower surface: Close to between 150D and 157A;            center and base moderately tinged with close to between            184C.        -   Peduncles.—Strength: Moderately strong. Length: About            20.8 cm. Diameter: About 7 mm. Aspect: About 10° from            vertical. Texture: Smooth, glabrous. Color: Close to 145C            moderately to heavily dotted with close to 182A to 182B.        -   Pedicels.—Strength: Moderately strong. Length: About 3.5 cm.            Diameter: About 2 mm. Aspect: Erect to about 20° from the            peduncle axis. Texture: Smooth, glabrous. Color: Close to            145C tinged with close to 176D.        -   Reproductive organs.—Stamens: Quantity per flower: About 70.            Filament length: About 1.5 cm. Filament color: Close to            157D. Anther shape: Reniform. Anther length: About 1.5 mm.            Anther color: Close to 150B to 150C. Pollen amount: Scarce.            Pollen color: Close to 158D. Pistils: Quantity per flower:            About six. Pistil length: About 1.1 cm. Stigma shape:            Club-shaped. Stigma color: Close to 157A. Style length:            About 1 cm. Style color: Close to 157D. Ovary color: Close            to 157C. Nectaries (transformed petals): Quantity per            flower: About 13. Length: About 9 mm. Diameter, apex: About            2 mm. Diameter, base: About 1 mm. Shape: Flattened            triangular. Color: Close to 145C; towards the base, close to            150B.        -   Seeds/fruits.—Seed and fruit development have not been            observed.-   Garden performance: Plants of the new Helleborus have been observed    to have good garden performance and to tolerate rain and wind.    Plants of the new Helleborus have been observed to tolerate high    temperatures of about 35° C. and are hardy to USDA Hardiness Zone 5.-   Pathogen/pest resistance: Plants of the new Helleborus have not been    shown to be resistant to pathogens and pests common to Helleborus.

1. A new and distinct Helleborus plant named ‘COSEH 790’ as illustratedand described.